Context : Models of magnetically-driven accretion and outflows reproduce many observational properties of T Tauri stars .
This concept is not well established for the more massive Herbig Ae/Be stars .

Aims : We intend to examine the magnetospheric accretion in Herbig Ae/Be stars and search for rotational modulation using spectroscopic signatures , in this first paper concentrating on the well-studied Herbig Ae star HD 101412 .

Methods : We used near-infrared spectroscopic observations of the magnetic Herbig Ae star HD 101412 to test the magnetospheric character of its accretion disk/star interaction .
We reduced and analyzed 30 spectra of HD 101412 , acquired with the CRIRES and X-shooter spectrographs installed at the VLT ( ESO , Chile ) .
The spectroscopic analysis was based on the He i \lambda 10,830 and Pa \gamma lines , formed in the accretion region .

Results : We found that the temporal behavior of these diagnostic lines in the near-infrared spectra of HD 101412 can be explained by rotational modulation of line profiles generated by accreting gas with a period P = 20 \aas@@fstack { d } 53 \pm 1 \aas@@fstack { d } 68 .
The discovery of this period , about half of the magnetic rotation period P _ { m } = 42 \aas@@fstack { d } 076 previously determined from measurements of the mean longitudinal magnetic field , indicates that the accreted matter falls onto the star in regions close to the magnetic poles intersecting the line-of-sight two times during the rotation cycle .
We intend to apply this method to a larger sample of Herbig Ae/Be stars .

Conclusions :